This invention relates to a lockset having an improved torque blade construction, the lockset being of the type wherein a bolt is reciprocal from and to a door edge by an operating mechanism including a crank hub and the crank hub is rotated by one or more torque blades, in turn, rotated by one or more actuating mechanisms, such as locks, mounted at faces of the door. Certain of the improvements of the present invention relate generally to the torque blade or blades operable connection to the crank hub of the operating mechanism for transmitting the rotative motion therebetween and to the bolt. Certain other of the improvements of the present invention relate generally to the torque blade or blades lost motion connection to the lock or locks of the lockset. Still other improvements of the present invention relate to the particular structure of the individual torque blades providing appreciable economics in fabrication, while still maintaining more than adequate strength and incorporating one or both of the foregoing improvements.
Various forms of locksets of the general type herein involved have been heretofore provided, all of which have included torque blades in one form or another between the lockset actuating mechanism or mechanisms and the bolt operating mechanism for transmitting the rotative motion therebetween. For instance, presenting the most complex situation to be encountered, assume that both outside and inside lockset actuating mechanisms are involved and that each of these actuating mechanisms is a keyed cylinder-type lock. The usual assembly will be a torque blade operably connected to the lock plug of the outside lock for selective rotation thereby with the torque blade extending partially into the crank hub of the bolt operating mechanism transmitting the rotative motion into extended and retracted movements of the bolt. A similar torque blade would be arranged in the same manner between the inside lock and the operating mechanism crank hub, this torque blade also extending into the crank hub a short distance in axial alignment with the outside lock torque blade. Furthermore, the lockset may be of the "single position assembly" type wherein the torque blades may only be assembled with the crank hub of the operating mechanism in a single predetermined position which insures that during the lockset assembly with the door, the lockset cannot be otherwise than properly assembled which must always result in proper operation after such assembly.
Assuming that the door thickness between faces thereof is compatible with the length of the respective outside and inside lock torque blades so that such torque blades engage in the crank hub of the operating mechanism a sufficient distance to provide proper strength for rotative motion transmission, these prior locksets have been satisfactorily serviceable. The problem arises, however, from the fact that various doors are of various thicknesses. This means that given a particular lockset model, doors with increased thicknesses will result in the respective torque blades engaging the crank hub each a lesser distance with the extreme being total non-engagement, and doors of lesser thickness will have the opposite result with the extreme being end abutment between the two torque blades preventing proper assembly of the locks on the door faces. This, therefore, has the overall result of requiring a relatively large number of lockset models in order to accommodate the varying thicknesses of doors.
Another factor of consideration is that nearly all modern key-actuated locks are constructed for key insertion and removal in a preset "neutral" position. From this neutral position, the key is rotated a partial turn in one direction to extend the lockset bolt and then reversely rotated back to "neutral" for key removal. The same procedure is followed but in the opposite rotative direction for retracting the bolt and then removing the key. The obvious requirement, therefore, is that between the lock plugs of each of the locks and their respective torque blades, there must be lost motion connections if the bolt is to remain in either of its extended or retracted positions while the key is rotated back to neutral for removal.
Although the prior lockset constructions have included the required lost motion connections, the principal difficulty therewith has been that of complexity. Due to the required formation thereof with insured proper operability, quite costly fabrication procedures have been involved which, in turn, add to the overall manufacturing expense of each lockset. Furthermore, such complexity can add appreciably to the production time involved in the original assembly of the locksets, again an additional fabrication expense which translates into ultimate additional consumer cost.